Which of the following methods is NOT a type of sterilization?

Fogging is the correct answer as it does not qualify as a sterilization method in the same way that the other options do. Sterilization refers to the process of killing all forms of microbial life, including bacteria, viruses, fungi, and spores, to ensure that an item is completely free from any viable microorganisms.

Moist heat, commonly used in autoclaving, effectively sterilizes by utilizing steam under pressure, which denatures proteins and destroys microbial cells. Dry heat sterilization is another method that utilizes higher temperatures to achieve sterilization, often through the process of oxidation of essential cell constituents.

Radiation, particularly ionizing radiation, is also a well-established method used to sterilize materials, especially medical and laboratory supplies, by disrupting the DNA of microorganisms.

Fogging, however, typically refers to a disinfection process that involves using a fog of chemical or non-chemical agents to reduce microbial presence in the environment, rather than killing all microorganisms to achieve complete sterilization. Therefore, it is not classified as a true sterilization method.